| 摘要 |
PROBLEM TO BE SOLVED: To detect a combined image of a reticle mark and a reference mark well by illuminating an imaginary plane through an alignment mark, reflecting the illumination light through a projection optical system and a reticle mark and illuminating the reference mark, and positioning a light shielding member at a position conjugate to the alignment mark. SOLUTION: Illumination light of an alignment system illuminates an imaginary plane A through a reticle mark RM and passes through a projection optical system 3 and a reference mark SM before entering a plane mirror 22. Illumination light reflected on the plane mirror 22 transmits through the reference mark SM from below. Illumination light passed through the reticle mark RM forms a combined image of the reference mark SM and the reticle mark RM on the image pickup plane of a two-dimensional image pickup element 15 and the positional shift of the reticle mark RM is detected using the reference mark SM as an index. A light shielding plate 20 is arranged optically in conjugate to the reticle mark RM forming plane by means of an illumination relay lens 18 and a first objective lens 12. |
